Photographic gelatin layer containing an ester of sulphosuccinic acid



, without drying, is overcoated with a Patented Apr. 29, 1941 PHOTOGRAPHIC GELATIN LAYER CONTAIN ING AN ESTER 0F SULPHOSUCCINIC ACID Norwood L. Simmons and Y., minors to Eastman Kodak Company, -Rochester, N. Y., a corporation 01' Rochester, N.

New Jersey Donald R. Swan,

No Drawing. Application March 12, 1940,

Serial No. 323,598

7 Claims, (Cl. 95-7) This invention relates to photographic lightsensitive materials, such as sensitized fllm, plates, and paper, comprising layers in which sensitive silver salts are suspended or dispersed in gelatin or other suitable vehicle, and optionally comprising other layers as well. More particularly, it relates to the use of certain agents to facilitate the spreading of gelatino-silver-halide layers and, in fact, the spreading of any gelatin or other hydrophilic colloid layers which are deposited from a predominantly aqueous medium and used in such photographic materials,

, Our invention perhaps finds its greatest use- 2 fuiness in the manufacture of photographic in which a sensitivegelatin emulsion layer is anpliedto the film base, set by chilling, and then, protective gelatin layer, the sensitive gelatin emulsion lay-=- er containing such a spreading agent, The gen eral process of coating film base with a sensitive gelatin emulsion layer, setting by chilling, and overcoating with a protective gelatin layer, is fully set forth in U. 8. Patent No. 1,699,349 of William E. Bailey.

Ii a sensitive gelatino-siiver-halide emulsion is coated on a film base (which has usually first been coated with a thin layer or suh stra of elatin or other colloid and dried) without the addition of a suitable spreading agent, culty is experienced in that the emulsion will spread unevenly. Moreover, if the emulsion, while still in a wet, chilled condition, is over-coated with a protective gelatin coating, air bubbles form be tween the emulsion layer and the protective lay- Eitherof these defects, of course, greatly impairs the quality of the photographic film.

It has, therefore, been customary in the art to add certain agents, such, for instance, as saponin, to the sensitive emulsionin order to avoid these defects as far as ible. Saponin has surface-active properties, and notoniy acts as a spreading agent for gelatin, but by some mechanism not clearly understood, it prevents the formation of air bubbles hetween the gelatin layers when a wet, chilled gelatin emulsion layer containing the proper concentration of saponin is overcoated with a warm gelatin solution.

However, saponin, being a' naturally occurring material of vegetable origin, is oi varying duality, and synthetic agents are to he preferred because or their more constant and controlled properties. Because cl its varying quality, some batches of saponin may cause an increase in fog or a decrease in sensitivity in the sensitive emulsion, and in some cases may produce little or no improvement in spreading. This is true whether the saponin be employed in the emulsion layer or in the protective overcoating or other layer.

Other surface-active materials have been tried in place of saponin, but many of them, while they may act to some extent as spreading agents for gelatin, have been found to be entirely in'efiective for preventing the formation of air bubbles when a wet, chilled gelatin emulsion cont w wthem is overcoated with a warm gelatin solution, and many of them are objectionable from the standpoint of logging or desensitizing the emul sion.

We have found a class of surface-active com pounds which are excellent spreading agents for gelatin and other hydrophilic colloid layers which are deposited from a predominantly aqueous medium and used in photographic films, plates, and paper. Moreover, a certain sub=class or this class of compounds, when incorporated in layers such as sensitive gelatin emulsions, are superior to saponinin the prevention of bubble formation when the wet, chilled emulsion layer is oven coated with a warm gelatin solution or other hydrophilic colloid oi the type which is deposited from a predominantly aqueous medium. The broad class of compounds are the water-soluble (sulpho) salts of the aliphatic esters of sulphm succinic acid. By the term "aliphatic esters. we mean 'tolnclude the alkyl and alkoxyalkyl monoand 'di-es ters. The sub-class above referred to as being useful in the prevention of bubble formation are the water-soluble (sulphol salts of the alkyl and a-lkoxyalkyl mono-esters of sulphasuccinic acid, in which the esterifying group contains from 8 to 18 carbon atoms, and of the di-= esters of sulphosuccinic acid in which at least one of the carboxyl groups is esterhied with an alkoxyalkyi group, i. e., of the aliphatic esters of sulphosuccinic acid containing at least one hydrophilic group in addition to the sulphonic radical. Examples of the sub-class are sodium di ethoxyethyl sulphosuccinate, sodium methcxyethyl lauryl sulphosuccinate, sodium methoxyethoxyethyl monodauroxyethoxyethyl sulphosuccinate. "In" the mono-esters, the unesterifled carbonyl group may be present in the free-form. or it may he lauryl sulphosuccinate, sodium. mono-iauroxyethyl sulphosuccinate, and sodium sulphosuccinate,

a film, plate, paper,

2 dihexyl sulphosuccinate, sodium ethyl lauryl sulphosuccinate, sodium dibutyl sulphosuccinate, sodium p-methoxybenzyl octyl sulphosuccinate,

sodium monolauryl sulphosuccinate, and sodium the ammonium salts, the alkylammonium salts,

and the alkylolammonium salts, the salt formation having taken place on the sulphonic acid group. a

These sulphosuccinic acid ester salts may be incorporated in the sensitive gelatin emulsion at any point in its manufacture such that they will be present during its coating, in the proportion of from 0.001 to 0.5 part of the compound per 100 parts by weight of Wet emulsion, if they are to'be used only as spreading agents. This gives a spreading agentcontent of 0.01% to 5% in the dried emulsion layer. If the emulsion is to be overooated, whileinthewet, chilled condition, with a warm gelatin solution, the spreading agent should be added to the emulsion in the proportion of from 0.005 to 0.5 part of ester salt per 100 parts by weight of wetemulsion. This gives a spreading agent content oi 0.05% to 5%- agents have no detrimental effect upon the photographic properties of the emulsion, but, on the contrary, improve them. It is believed that the property of the spreading agent-which prevents the formation of air bubbles when a wet, chilled gelatin emulsion is overcoated with a warm gelatin-solution, also tends to prevent the formation of air bubbles, repellent spots, etc., on the surface of a sensitive eniulsion containing such a spreading agent, when that emulsion, coated: on etc., is immersed in a de-' veloper. I

These sulpho'succinic acid ester salts may be used as dispersing agents for the monoesters of sorbitol when the latter are employed in photographic hydrophilic colloid layers, as disclosed 321,901, filed March 2, 1940.

in an applicationof Donald R. Swan, Serial No.

As above pointed out, the sulphosuccinic acid as film, glass, paper, etc., which layers consist of gelatin or other hydrophilic colloid which is deposited from a predominantly aqueous medium, i. e., amedium used as the solvent for such. materials in which water predominates, the remainder of the medium contributing to give a philic colloids other than gelatin, which are useful as layers in photographic -films,,plates, paper, etc., are the water-soluble cellulose derivatives such as well hydrolyzed cellulose acetate (described in U. S. Patent No. 2,110,491 oi.Salo) and cellulose esters .oihydroxy monocarboxylic acids,

such as lactic or glycolic, and salts of cellulose esters of dicarboxylic acids, such as phthalic described in U. S. Patent No. 2,127,573 of Shepard and U. S. Patent No. 2,127,621 of Stand) as well as polyvinyl alcohol .and ihydrolyzed polyvinyl acetate (described in-applications of Wesley G. Lowe, Serial Nos. 318,559 and 318,560, filed February 12, 1940), and water-soluble polyvinyl acetals (described in an application of Charles R.

In the claims appended hereto, where a hy drophilic' colloid depositable from a predominantly aqueous medium{ is referred to, it will be understood to mean 'any hydrophilic colloid which can be deposited from a medium which is predominantly aqueous, the remainder of the medium being an organic solvent which contributes to the dispe'rsability of the colloid; examples of such organicsolvents for this purpose are acetone, ethyl alcohol, ethylene glycol, monoace- 30 tin and pyridine.

What we claim as our invention and desire to be secured by Letters Patent of the United States 1. Photographic sensitive material comprising a layer of a hydrophilic colloid depositable from a predominantly aqueous medium, said layer containing from 0.01% to 5% of a water-soluble 'sulpho salt of an aliphatic ester of sulphosuccinic acid.

2. Photographic sensitive material comprising a base and two superposed gelatin layers, in

which the gelatin layer nearer the base contains from 0.05% to 5% of a water-soluble sulpho salt of an aliphatic ester of sulphosuccinic acid containing at least one hydrophilic group in addition to the sulphonic radical.

- 4. Photographic sensitive material comprisinga base, a photo-sensitive gelatin emulsion layerv and a gelatin overcoating on the emulsion, in

' which the photo-sensitive gelatin emulsion laygood dispersion of the colloid. .If two superposed colloid layers are present, either, neither'or both of which may be photographically sensitive, the

sensitive gelatin or similar layer is' to be over-'1.

coated with a warm solution or emulsion of gela- ,tin or similar material; the presence of the spreading agent in the wet, chilled layer is essential forpreventing the formation of air hubor contains from 0.05% to 5% 01' a water -soluble sulpho salt of an aliphatic ester of sulphosuccinic' acid containing at least one hydrophilic group in addition to thesulphonic radical.

5. Photographic sensitive material comprising a gelatin layer containing from 0.01% to 5% of the sodium .salt of dioctyl sulphosuccinate.

6. Photographic sensitive material comprisin a gelatin layer containing from 0.01% to 5% of bles between the layers, and for this purpose either an unesterifled carboxyl group or an alkoxyalkyl group must be present in the sulpho 

